Heat exchange apparatus

ABSTRACT

A heat exchange apparatus comprises an evaporation unit  1  for exchanging heat between a working fluid and a high-temperature fluid to thereby evaporate the working fluid, a condenser unit for exchanging heat between the working fluid and a low-temperature fluid to thereby condense the working fluid, an evaporation-side communication unit  5   a  for leading the working fluid evaporated in the evaporation unit  1  to the condenser unit  2,  and a condenser-side communication unit  5   b  for leading the working fluid condensed in the condenser unit  2  to the evaporation unit  1.  The high-temperature fluid is prevented by condenser-side shield plates  101, 102  from flowing to the condenser-side communication unit  5   b . As a result, the heating and evaporation of the working fluid in the condenser-side communication unit  5   b  by the high-temperature fluid is prevented or reduced thereby preventing a dry-out phenomenon.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a heat exchange apparatus using heat pipes.

2. Description of the Related Art

A conventional heat exchange apparatus is known which recovers exhaust heat of exhaust gas of an internal combustion engine (hereinafter referred to simply as engine) of an automotive vehicle and utilizes the exhaust heat to warm-up an engine.

Also, JP4-45393A discloses a loop-type heat-pipe heat exchange apparatus using heat pipes for a water heating system. In this heat exchange apparatus, an evaporable and condensable working fluid is circulated in a circulation path of a closed loop, evaporated by absorbing heat from a heat storage member in an evaporation unit and condensed by releasing the heat to water in a condenser unit. Also, the lower end portions of a plurality of heat pipes communicate with each other through a lower header (hereinafter referred to as a condenser-side communication unit), so that the working fluid condensed in the condenser unit flows into the plurality of the heat pipes through the condenser-side communication net.

SUMMARY OF THE INVENTION

In the case where the heat exchange apparatus disclosed in JP4-45393A is used for recovery of the exhaust heat of the exhaust gas, the condenser-side communication unit is also exposed to high-temperature exhaust gas and heats and evaporates the working fluid, resulting in what is called a “dry-out” phenomenon in which the liquid-phase working fluid fails to arrive at the evaporation unit (i.e. the heat pipes and the outer fins) having a large heat receiving capacity. As a result, the heat pipes cannot be used effectively and heat exchange performance is deteriorated.

In view of the points described above, the object of this invention is to provide a loop-type heat-pipe heat exchange apparatus applicable to a heat source in the form of a fluid.

According to a first aspect of the invention, there is provided a heat exchange apparatus comprising a first housing (100) with a high-temperature fluid flowing therein, a second housing (200) with a low-temperature fluid flowing therein, an evaporation unit (1) for exchanging heat between the working fluid and the high-temperature fluid to thereby evaporate the working fluid, a condenser unit (2) for exchanging heat between the working fluid and the low-temperature fluid to thereby condense the working fluid, an evaporation-side communication unit (5 a) for leading the working fluid evaporated in the evaporation unit (2) to the condenser unit (2), and a condenser-side communication unit (5 b) for leading the working fluid condensed in the condenser unit (2) to the evaporation unit (1), wherein the high-temperature fluid is prevented from flowing to the condenser-side communication unit (5 b).

With this configuration, the chance of the working fluid being heated and evaporated in the condenser-side communication unit (5 b) by the high-temperature fluid can be eliminated or reduced, and therefore, dry-out is prevented for improved heat exchange performance.

In this case, condenser-side shield plates (8 a, 8 b; 101, 102), which can be used to prevent the high-temperature fluid from flowing to the condenser-side communication unit (5 b), may be arranged integrally with the first housing (100) or the evaporation unit (1).

Also, the condenser-side shield plate (8 a; 101) may be arranged upstream of the condenser-side communication unit (5 b) in the flow of the high-temperature fluid.

By doing so, the high-temperature fluid can be prevented from flowing to the surface of the condenser-side communication unit (5 b) upstream in the flow of the high-temperature fluid.

Also, the condenser-side shield plates (8 a, 8 b; 101, 102) can be arranged upstream or downstream of the condenser-side communication unit (5 b) in the flow of the high-temperature fluid.

By doing so, the high-temperature fluid can be prevented from flowing to the surface of the condenser-side communication unit (5 b) upstream in the flow of the high-temperature fluid on the one hand, and the high-temperature fluid can be prevented from flowing to the surface of the condenser-side communication unit (5 b) downstream in the flow of the high-temperature fluid on the other hand. Thus, dry-out can be prevented.

Also, the condenser-side shield plate (101) arranged upstream of the condenser-side communication unit (5 b) in the flow of the high-temperature fluid can be configured to reduce the area of the path in the first housing (100) continuously toward the evaporation unit (1) from the upstream side of the high-temperature fluid flow.

By doing so, the high-temperature fluid smoothly flows into the evaporation unit (1) and disturbance of the flow can be suppressed. As a result, heat exchange between the high-temperature fluid and the working fluid in the evaporation unit (1) can be successfully performed.

Also, the first housing (100) may include an enlarged portion (132) having an enlarged path area and the condenser-side communication unit (5 b) can be arranged in the enlarged portion (132).

By doing so, the high-temperature fluid can be prevented from flowing to the condenser-side communication unit (5 b).

Also, the high-temperature fluid generates condensed water by heat exchange with the working fluid, and the apparatus may include a condensed water path (1023) for removing condensed water pooled around the condenser-side communication unit (5 b) downstream of the condenser-side communication unit (5 b) in the flow of the high-temperature fluid.

By doing so, condensed water pooled around the condenser-side communication unit (5 b) can be removed downstream.

Also, the high-temperature fluid generates condensed water by heat exchange with the working fluid, and the apparatus may include a condensed water path (132 c) for discharging the condensed water pooled around the condenser-side communication unit (5 b) outside of the first housing (100).

By doing so, condensed water pooled around the condenser-side communication unit (5 b) can be discharged outside.

Also, the condenser-side communication unit (5 b) can be projected out from the first housing (100).

By doing so, the high-temperature fluid can be prevented from flowing to the condenser-side communication unit (5 b).

Also, the high-temperature fluid can be prevented from flowing through gaps between the outer peripheral surfaces of the evaporation unit (1), the evaporation-side communication unit (5 a) and the condenser-side communication unit (5 b) on the one hand and the inner peripheral surface of the first housing (100) on the other hand.

By doing so, the ratio of the amount of high-temperature fluid flowing through the evaporation unit (1) which represents of the total amount of the high-temperature fluid flowing in the first housing (100) is increased, and therefore, heat exchange between the high-temperature fluid and the working fluid is successfully conducted.

Also, the apparatus may include condenser-side shield plates (101, 102) in order to prevent the high-temperature fluid from flowing through the gap between the outer peripheral surface of the condenser-side communication unit (5 b) and the inner peripheral surface of the first housing (100), and evaporation-side shield plates (111, 112) in order to prevent the high-temperature fluid from flowing through the gap between the outer peripheral surface of the evaporation-side communication unit (5 a) and the inner peripheral surface of the first housing (100).

Also, the apparatus may be configured so that the condenser-side shield plate (101) and the evaporation-side shield plate (111) are arranged upstream of the condenser-side communication unit (5 b) in the flow of the high-temperature fluid and the area of the path in the first housing (100) is continuously decreased toward the evaporation unit (1) from the upstream side of the high-temperature fluid flow.

By doing so, the high-temperature fluid smoothly flows to the evaporation unit (1) and disturbance of the flow can be suppressed. Therefore, heat exchange between the high-temperature fluid and the working fluid in the evaporation unit (1) can be smoothly carried out.

Also, the apparatus may be configured so that the condenser-side shield plate (102) and the evaporation-side shield plate (112) are arranged downstream of the condenser-side communication unit (5 b) in the high-temperature fluid flow, and the area of the path in the first housing (100) is continuously increased from the evaporation unit (1) toward the downstream side of the high-temperature fluid flow.

By doing so, the high-temperature fluid flows out of the evaporation unit (1) smoothly and smooth gas flow is obtained. Thus, heat exchange between the exhaust gas and the working fluid can be smoothly conducted.

Water can also be used as the working fluid.

Further, the exhaust gas discharged from the water-cooled internal combustion engine can be used as the high-temperature fluid, and the cooling water of the water-cooled internal combustion engine as the low-temperature fluid.

By doing so, the exhaust heat can be utilized in order to warm-up the engine. A vehicle equipped with a heating apparatus using the engine cooling water as a heat source can also be heated more quickly during the engine warming-up operation.

According to a second aspect of the invention, there is provided a heat exchange apparatus comprising an evaporation unit (1) arranged in a high-temperature fluid path with a high-temperature fluid flowing therein for exchanging heat between the working fluid and the high-temperature fluid thereby to evaporate the working fluid, a condenser unit (2) arranged in a low-temperature fluid path with a low-temperature fluid flowing therein for exchanging heat between the working fluid and the low-temperature fluid thereby to condense the working fluid, an evaporation-side communication unit (5 a) for leading the working fluid evaporated in the evaporation unit (1) to the condenser unit (2), and a condenser-side communication unit (5 b) for leading the working fluid condensed in the condenser unit (2) to the evaporation unit (1), wherein the high-temperature fluid is prevented from flowing to the condenser-side communication unit (5 b).

With this configuration, the chance of the working fluid being heated and evaporated by the high-temperature fluid in the condenser-side communication unit (5 b) can be eliminated or reduced, and therefore, dry-out can be prevented for improved heat exchange performance.

Incidentally, the reference numerals inserted in the parentheses following the names of the respective means described above indicate the correspondence with the specific means described below in the embodiments.

The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a heat exchange apparatus according to a first embodiment of the invention as taken from the upstream side of the exhaust gas flow.

FIG. 2 is a front sectional view of the heat exchange apparatus according to the first embodiment.

FIG. 3 is a schematic sectional view taken along line A-A in FIG. 1.

FIG. 4 is a front view of a heat exchange apparatus according to a second embodiment of the invention as taken from the upstream side of the exhaust gas flow.

FIG. 5 is a schematic sectional view taken along line C-C in FIG. 4.

FIG. 6 is a schematic sectional view showing a heat exchange apparatus according to a third embodiment of the invention.

FIG. 7 is a schematic sectional view showing a heat exchange apparatus according to a fourth embodiment of the invention.

FIG. 8 is a schematic sectional view showing a heat exchange apparatus according to a fifth embodiment of the invention.

FIG. 9 is a schematic sectional view showing a heat exchange apparatus according to a sixth embodiment of the invention.

FIG. 10 is a schematic sectional view showing a heat exchange apparatus according to a seventh embodiment of the invention.

FIG. 11 is a schematic sectional view showing a heat exchange apparatus according to an eighth embodiment of the invention.

FIG. 12 is a schematic sectional view showing a heat exchange apparatus according to a ninth embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

A first embodiment of the invention will be explained. In the heat exchange apparatus according to this embodiment, the exhaust heat of the exhaust gas is recovered from the exhaust system of the water-cooled engine of the automotive vehicle to heat the engine cooling water, and the heated engine cooling water is used as a heat source for a climate control system or the like.

FIG. 1 is a front view of the heat exchange apparatus according to this embodiment as taken from the upstream side of the exhaust gas flow. FIG. 2 is a front sectional view of the heat exchange apparatus according to this embodiment, and FIG. 3 a schematic sectional view taken along line A-A in FIG. 1.

As shown in FIGS. 1 to 3, the heat exchange apparatus according to this embodiment comprises a cylindrical first housing 100 with the exhaust gas flowing therein as a high-temperature in the direction of arrow B (FIG. 3) therein, a second housing 200 with the engine cooling water flowing therein as a low-temperature fluid, and a heat exchanger 300 for absorbing heat from the exhaust gas and releasing the heat into the engine cooling water. The first housing 100, the second housing 200 and the heat exchanger 300 are integrated with each other before being coupled to the engine exhaust pipe not shown or the engine cooling water pipe not shown.

The first housing 100, which is arranged midway of and coupled to the engine exhaust pipe, constitutes a part of the exhaust pipe. The second housing 200, which is arranged midway of and coupled to the engine cooling water pipe, constitutes a part of the cooling water pipe. The heat exchanger 300 includes an evaporation unit 1 and the condenser unit 2 arranged adjacently to each other.

The evaporation unit 1 is arranged in the first housing 100 and exchanges heat between the exhaust gas and a working fluid described later thereby to evaporate the working fluid. The condenser unit 2, arranged in the second housing 200, exchanges heat between the working fluid evaporated in the evaporation unit 1 and the engine cooling water thereby to condense the working fluid.

The evaporation unit 1 has a plurality of evaporation-side heat pipes 3 a. The plurality of the evaporation-side heat pipes 3 a each have a flat form so that the direction in which the exhaust gas flows (the direction perpendicular to the page in FIG. 1) coincides with the direction of the long side thereof on the one hand, and are arranged in parallel to each other so that the longitudinal direction thereof coincides with the vertical direction on the other hand. The flat surface on each side of each evaporation-side heat pipes 3 a is coupled with a corrugated outer fin 4 a, whereby the area of heat transmission to and from the exhaust gas is increased thereby to promote the heat exchange between the working fluid and the exhaust gas.

The condenser unit 2 has a plurality of condenser-side heat pipes 3 b. The plurality of the condenser-side heat pipes 3 b each have a flat form so that the direction in which the engine cooling water flows (the direction perpendicular to the page in FIG. 1) coincides with the direction of the long side thereof on the one hand, and are arranged in parallel to each other so that the longitudinal direction thereof coincides with the vertical direction on the other hand. More specifically, the condenser-side heat pipes 3 b are arranged so that the longitudinal direction thereof coincides with the longitudinal direction of the evaporation-side heat pipes 3 a. Also, straight fins 4 b are coupled to the flat surface on each side of the condenser-side heat pipes 3 b, whereby the area of heat transmission to and from the engine cooling water is increased thereby to promote the heat exchange between the working fluid and the engine cooling water.

A pair of communication units 5 a, 5 b extending in the direction orthogonal to the length of the heat pipes 3 a, 3 b and communicating with all the heat pipes 3 a, 3 b are arranged at the longitudinal (vertical) ends of the heat pipes 3 a, 3 b, respectively. The working fluid evaporated in the evaporation unit 1 is led to the condenser unit 2 by the evaporation-side communication unit 5 a arranged on the vertically upper side, while the working fluid condensed in the condenser unit 2 is led to the evaporation unit 1 by the condenser-side communication unit 5 b arranged on the vertically lower side.

The heat pipes 3 a, 3 b and the communication unit pair 5 a, 5 b make up a closed loop, which has sealed therein the evaporable and condensable working fluid (water in this embodiment). Incidentally, the amount of the working fluid is set at least in such a manner that the liquid level is located above the condenser-side communication unit 5 b.

A side plate 7 extending substantially in parallel to the length of the evaporation-side heat pipes 3 a and reinforcing the evaporation unit 1 is arranged at each end of the evaporation unit 1.

The first housing 100 includes condenser-side shield plates 101, 102 for preventing the exhaust gas from flowing to the condenser-side communication unit 5 b while at the same time preventing the exhaust gas from flowing through the gap between the outer peripheral surface of the condenser-side communication unit 5 b and the inner peripheral surface of the first housing 100.

More specifically, the first condenser-side shield plate 101 arranged upstream of the condenser-side communication unit 5 b in the exhaust gas flow includes a cover plate portion 1011 arranged orthogonally to the direction in which the exhaust gas flow to cover the surface of the condenser-side communication unit 5 b upstream in the exhaust gas flow and a swash plate portion 1012 arranged diagonally to the direction in which the exhaust gas flows for reducing the area of the path in the first housing 100 continuously from the upstream side of the exhaust gas flow toward the evaporation unit 1.

The second condenser-side shield plate 102 arranged downstream of the condenser-side communication unit 5 b in the exhaust gas flow includes a cover plate portion 1021 arranged orthogonally to the direction in which the exhaust gas flows to cover the surface of the condenser-side communication unit 5 b downstream in the exhaust gas flow and a swash plate portion 1022 arranged diagonally to the direction in which the exhaust gas flows to continuously increase the area of the path in the first housing 100 from the evaporation unit 1 toward the downstream side of the exhaust gas flow.

The first housing 100 also, includes evaporation-side shield plates 111, 112 for smoothing the exhaust gas flow in the neighborhood of the evaporation-side communication unit 5 a while at the same time preventing the exhaust gas from flowing through the gap between the outer peripheral surface of the evaporation-side communication unit 5 a and the inner peripheral surface of the first housing 100. More specifically, the first evaporation-side shield plate 111 arranged upstream of the evaporation-side communication unit 5 a in the exhaust gas flow includes a cover plate portion 1111 arranged in the direction perpendicular to the direction in which the exhaust gas flows to cover the surface of the evaporation-side communication unit 5 a upstream in the exhaust gas flow and a swash plate portion 1112 arranged diagonally to the direction in which the exhaust gas flows to reduce the area of the path in the first housing 100 continuously from the upstream side of the exhaust gas flow toward the evaporation unit 1. The second evaporation-side shield plate 112 arranged downstream of the evaporation-side communication unit 5 a in the exhaust gas flow includes a cover plate portion 1121 arranged in the direction perpendicular to the direction in which the exhaust gas flows to cover the surface of the evaporation-side communication unit 5 a downstream in the exhaust gas flow and a swash plate portion 1122 arranged diagonally to the direction in which the exhaust gas flows to increase the area of the path in the first housing 100 continuously from the evaporation unit 1 toward the downstream side of the exhaust gas flow.

In the heat exchange apparatus according to this embodiment having the configuration described above, the exhaust gas flows through the evaporation unit 1 so that the liquid-phase working fluid in the evaporation-side heat pipe 3 a evaporates by absorbing heat from the exhaust gas, and the gas-phase working fluid flows into the condenser unit 2 through the evaporation-side communication unit 5 a. The gas-phase working fluid flowing in the condenser-side heat pipes 3 b is condensed by releasing heat to the engine cooling water, and the working fluid thus condensed flows into the evaporation unit 1 through the condenser-side communication unit 5 b.

In this way, the first condenser-side shield plate 101 prevents the exhaust gas from flowing to the surface of the condenser-side communication unit 5 b upstream in the exhaust gas flow on the one hand, and the second condenser-side shield plate 102 prevents the exhaust gas from flowing to the surface of the condenser-side communication unit 5 b downstream in the exhaust gas flow on the other hand. As a result, the working fluid is prevented from being evaporated in the condenser-side communication unit 5 b by being heated by the exhaust gas, and the liquid-phase working fluid is positively supplied also to the part of the condenser-side communication unit 5 b far from the condenser unit 2. Thus dry-out is prevented and heat exchange performance is improved.

Also, in view of the fact that the swash plate portions 1012, 1112 of the first condenser-side shield plate 101 and the first evaporation-side shield plate 111 cause the exhaust gas to flow smoothly into the evaporation unit 1, while at the same time, the swash plate portions 1022, 1122 of the second condenser-side shield plate 102 and the second evaporation-side shield plate 112 cause the exhaust gas to flow out smoothly from the evaporation unit 1 to secure a satisfactory gas flow. Thus, the heat exchange is carried out successfully between the exhaust gas and the working fluid.

Also, the first condenser-side shield plate 101 and the second condenser-side shield plate 102 prevent the exhaust gas from flowing through the gap between the outer peripheral surface of the condenser-side communication unit 5 b and the inner peripheral surface of the first housing 100. Further, the first evaporation-side shield plate 111 and the second evaporation-side shield plate 112 prevent the exhaust gas from flowing through the gap between the outer peripheral surface of the evaporation-side communication unit 5 a and the inner peripheral surface of the first housing 100. Thus, the exhaust gas flow is concentrated in the evaporation unit 1. Specifically, the ratio of the amount of the exhaust gas flowing through the evaporation unit 1 which represents of the total amount of the exhaust gas flowing in the first housing 100 increases, resulting in the successful heat exchange between the exhaust gas and the working fluid. Incidentally, by closing a gap, if any, between the first housing 100 and the side plate 7, the exhaust gas flows only in the evaporation unit 1 and therefore the heat exchange between the exhaust gas and the working fluid becomes more successful.

Second Embodiment

A second embodiment of the invention will be explained. FIG. 4 is a front view showing the heat exchange apparatus according to this embodiment as taken from the upstream side of the exhaust gas flow, and FIG. 5 a schematic sectional view taken along line C-C in FIG. 4. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and not described any more.

As shown in FIGS. 4 and 5, the first housing 100 includes a tubular portion 131 substantially identical with the evaporation unit 1 in the shape and dimensions as viewed from the direction in which the exhaust gas flows and a tubular enlarged portion 132 substantially identical with the evaporation unit 1 in the shape and dimensions as viewed from the direction in which the exhaust gas flows and having a larger area of the path than the tubular portion 131.

The evaporation-side communication unit 5 a is arranged in the vertically upper enlarged portion 132 a of the enlarged portion 132, while the condenser-side communication unit 5 b is arranged in the vertically lower enlarged portion 132 b of the enlarged portion 132. Also, the evaporation unit 1 and the tubular portion 131 are arranged in such a manner as to share the same projection plane as viewed along the direction in which the exhaust gas flows. Therefore, the exhaust gas in the first housing 100 flows not to the evaporation-side communication unit 5 a or the condenser-side communication unit 5 b but only through the evaporation unit 1.

According to this embodiment, the working fluid is prevented from being evaporated in the condenser-side communication unit 5 b by being heated by the exhaust gas, and the liquid-phase working fluid is positively supplied also to the part of the condenser-side communication unit 5 b far from the condenser unit 2. As a result, dry-out is suppressed for improved heat exchange performance.

Also, the exhaust gas flow is concentrated in the evaporation unit 1, and therefore, the heat exchange between the exhaust gas and the working fluid is conducted successfully.

Third Embodiment

A third embodiment of the invention will be explained. FIG. 6 is a schematic sectional view of the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and not explained any further.

As shown in FIG. 6, the first housing 100 includes a tubular portion 141 substantially identical with the evaporation unit 1 in shape and dimensions as viewed along the direction in which the exhaust gas flows and openings 142 substantially identical in shape and dimensions to the evaporation unit 1 as viewed in vertical direction.

The evaporation-side communication unit 5 a and the condenser-side communication unit 5 b are projected out from the first housing 100 from the openings 142, and the evaporation unit 1 is arranged inside the first housing 100.

According to this embodiment, the working fluid is prevented from being evaporated in the condenser-side communication unit 5 b by being heated by the exhaust gas, and the liquid-phase working fluid is positively supplied also to the part of the condenser-side communication unit 5 b far from the condenser unit 2. Therefore, dry-out is prevented and the heat exchange performance improved.

Also, since the exhaust gas flow is concentrated in the evaporation unit 1, the exhaust gas and the working fluid exchange heat successfully with each other.

Fourth Embodiment

A fourth embodiment of the invention will be explained. FIG. 7 is a schematic sectional view of the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and not explained any further.

As shown in FIG. 7, a condensed water path 1023 for establishing communication between the upstream and downstream sides of the second condenser-side shield plate 102 of the first housing 100 in the exhaust gas flow is formed in the vertically lowest part of the second condenser-side shield plate 102.

According to this embodiment, the part of the condensed water generated by heat exchange between the exhaust gas and the working fluid which stays around the condenser-side communication unit 5 b is removed downstream of the condenser-side communication unit 5 b in the exhaust gas flow through the condensed water path 1023.

Fifth Embodiment

A fifth embodiment of the invention will be explained. FIG. 8 is a schematic sectional view of the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the second embodiment are designated by the same reference numerals, respectively, and not explained any further.

As shown in FIG. 8, the first housing 100 is so constructed that a pipe-like condensed water path 132 c for connecting the space in the lower enlarged portion 132 b and the exterior of the first housing 100 is arranged in the vertically lowest part of the lower enlarged portion 132 b.

According to this embodiment, that part of the condensed water generated by heat exchange between the exhaust gas and the working fluid which stays around the condenser-side communication unit 5 b (i.e. in the lower enlarged portion 132 b) is discharged out of the first housing 100 through the condensed water path 132 c.

Sixth Embodiment

A sixth embodiment of the invention will be explained. FIG. 9 is a schematic sectional view showing the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and is not further described.

As shown in FIG. 9, condenser-side shield plates 8 a, 8 b for preventing the exhaust gas from flowing to the condenser-side communication unit 5 b are arranged integrally with the evaporation unit 1. More specifically, the first condenser-side shield plate 8 a arranged upstream of the condenser-side communication unit 5 b in the exhaust gas flow is coupled to the surface of the condenser-side communication unit 5 b upstream in the exhaust gas flow. The second condenser-side shield plate 8 b arranged downstream of the condenser-side communication unit 5 b in the exhaust gas flow, on the other hand, is coupled to the surface of the condenser-side communication unit 5 b downstream in the exhaust gas flow. The condenser-side shield plates 8 a, 8 b are formed of a material lower in heat conductivity than the condenser-side communication unit 5 b to reduce the heat transmitted from the exhaust gas to the condenser-side communication unit 5 b.

According to this embodiment, the heat transmission from the exhaust gas to the condenser-side communication unit 5 b is suppressed by the condenser-side shield plates 8 a, 8 b. As a result, the condenser-side communication unit 5 b prevents the working fluid from being evaporated by being heated by the exhaust gas, so that the liquid-phase working fluid can be positively supplied also to the part of the condenser-side communication unit 5 b far from the condenser unit 2. Therefore, dry-out is prevented resulting in improved heat exchange performance.

Seventh Embodiment

A seventh embodiment of the invention will be explained. FIG. 10 is a schematic sectional view showing the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and not described any further.

As shown in FIG. 10, the shield plates 101, 102 111, 112 have parallel plate portions 1013, 1023, 1113, 1123 extending in parallel to the exhaust gas flow between the cover plate portions 1011, 1021, 1111, 1121 and the swash plate portions 1012, 1022, 1112, 1122, respectively.

According to this embodiment, the exhaust gas flows more smoothly into and out of the evaporation unit 1. Thus, a satisfactory gas flow is obtained, and therefore, the heat exchange between the exhaust gas and the working fluid is carried out successfully.

Eighth Embodiment

An eighth embodiment of the invention is explained. FIG. 11 is a schematic sectional view showing the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and is not further described.

As shown in FIG. 11, the swash plate portion 1012 of the first condenser-side shield plate 101 and the swash plate portion 1112 of the first evaporation-side shield plate 111 are configured in arcuate form to reduce the area of the path in the first housing 100 first steeply and then gradually from the upstream side of the exhaust gas flow toward the evaporation unit 1.

Also, the swash plate portion 1022 of the second condenser-side shield plate 102 and the swash plate portion 1122 of the second evaporation-side shield plate 112 are configured in arcuate form to increase the area of the path in the first housing 100 first gradually and then steeply from the evaporation unit 1 toward the downstream side of the exhaust gas flow.

Ninth Embodiment

A ninth embodiment of the invention will be explained. FIG. 12 is a schematic sectional view showing the heat exchange apparatus according to this embodiment. The component parts identical or equivalent to those of the first embodiment are designated by the same reference numerals, respectively, and not described any further.

As shown in FIG. 12, the swash plate portion 1012 of the first condenser-side shield plate 101 and the swash plate portion 1112 of the first evaporation-side shield plate 111 are configured in arcuate form to reduce the area of the path in the first housing 100 first gradually and then steeply from the upstream side of the exhaust gas flow toward the evaporation unit 1.

Also, the swash plate portion 1022 of the second condenser-side shield plate 102 and the swash plate portion 1122 of the second evaporation-side shield plate 112 are configured in arcuate form to increase the area of the path in the first housing 100 first steeply and then gradually from the evaporation 1 toward the downstream side of the exhaust gas flow.

Other Embodiments

In each embodiment described above, the first housing 100, after being integrated with the heat exchanger 300, is coupled to the engine exhaust pipe. As an alternative, the heat exchanger 300 may be coupled to the first housing 100 after coupling the first housing 100 to the engine exhaust pipe.

Also, according to each of the embodiments described above, the evaporation unit 1 and the condenser unit 2 are arranged adjacently to each other. The invention is not limited to this configuration, and the evaporation unit 1 and the condenser unit 2 may be arranged in spaced relation to each other.

Also, the plurality of the heat pipes 3 a, 3 b, instead of being arranged with the length thereof in a vertical direction as in each of the embodiments described above, may alternatively be arranged in a non-horizontal direction at an angle to the vertical direction as long as the condensed working fluid exists in the lowest part of the heat pipes 3 a, 3 b.

Also, unlike each of the embodiments described above, the apparatus according to the invention may include one instead of a plurality of the evaporation-side heat pipes 3 a.

While the invention has been described by reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention. 

1. A heat exchange apparatus comprising: a first housing with a high-temperature fluid flowing therein; a second housing with a low-temperature fluid flowing therein; an evaporation unit arranged in the first housing for exchanging heat between an evaporable and condensable working fluid sealed therein and the high-temperature fluid thereby to evaporate the working fluid; a condenser unit arranged in the second housing for exchanging heat between the working fluid evaporated in the evaporation unit and the low-temperature fluid thereby to condense the working fluid; an evaporation-side communication unit for leading the working fluid evaporated in the evaporation unit to the condenser unit; and a condenser-side communication unit for leading the working fluid condensed in the condenser unit to the evaporation unit; wherein the evaporation unit includes a plurality of heat pipes arranged in such a manner that the working fluid flows in a non-horizontal direction and a plurality of outer fins for increasing the area of heat transmission between the heat pipes and the high-temperature fluid; wherein the working fluid is circulated between the evaporation unit and the condenser unit; and wherein the high-temperature fluid is prevented from flowing to the condenser-side communication unit.
 2. The heat exchange apparatus according to claim 1, further comprising a plurality of condenser-side shield plates for preventing the high-temperature fluid from flowing to the condenser-side communication unit
 3. The heat exchange apparatus according to claim 2, wherein the condenser-side shield plates are arranged integrally with the first housing.
 4. The heat exchange apparatus according to claim 2, wherein the condenser-side shield plates are arranged integrally with the evaporation unit.
 5. The heat exchange apparatus according to claim 2, wherein the condenser-side shield plates are arranged upstream of the condenser-side communication unit in the flow of the high-temperature fluid.
 6. The heat exchange apparatus according to claim 2, wherein the condenser-side shield plates are arranged both upstream and downstream of the condenser-side communication unit in the flow of the high-temperature fluid.
 7. The heat exchange apparatus according to claim 6, wherein the condenser-side shield plate arranged upstream of the condenser-side communication unit in the flow of the high-temperature fluid is configured to reduce the area of the path in the first housing continuously toward the evaporation unit from the upstream side of the high-temperature fluid flow.
 8. The heat exchange apparatus according to claim 1, wherein the first housing includes an enlarged portion having an enlarged path area and the condenser-side communication unit is arranged in the enlarged portion.
 9. The heat exchange apparatus according to claim 1, wherein the high-temperature fluid generates the condensed water by exchanging heat with the working fluid, and a condensed water path is formed to remove the condensed water staying around the condenser-side communication unit downstream of the condenser-side communication unit in the flow of the high-temperature fluid.
 10. The heat exchange apparatus according to claim 1, wherein the high-temperature fluid generates the condensed water by exchanging heat with the working fluid, and a condensed water path is formed to discharge the condensed water staying around the condenser-side communication unit outside of the first housing.
 11. The heat exchange apparatus according to claim 1, wherein the condenser-side communication unit is projected out from the first housing.
 12. The heat exchange apparatus according to claim 1, wherein the high-temperature fluid is prevented from flowing through the gaps between the outer peripheral surfaces of the evaporation unit, the evaporation-side communication unit and the condenser-side communication unit on the one hand and the inner peripheral surface of the first housing on the other hand.
 13. The heat exchange apparatus according to claim 12, further comprising: a condenser-side shield plate for preventing the high-temperature fluid from flowing through the gap between the outer peripheral surface of the condenser-side communication unit and the inner peripheral surface of the first housing; and an evaporation-side shield plate for preventing the high-temperature fluid from flowing through the gap between the outer peripheral surface of the evaporation-side communication unit and the inner peripheral surface of the first housing.
 14. The heat exchange apparatus according to claim 13, wherein the condenser-side shield plate and the evaporation-side shield plate are arranged upstream of the condenser-side communication unit in the flow of the high-temperature fluid, and the area of the path in the first housing is continuously decreased toward the evaporation unit from the upstream side of the high-temperature fluid flow.
 15. The heat exchange apparatus according to claim 13, wherein the condenser-side shield plate and the evaporation-side shield plate are arranged downstream of the condenser-side communication unit in the flow of the high-temperature fluid, and the area of the path in the first housing is continuously increased from the evaporation unit toward the downstream side of the high-temperature fluid flow.
 16. The heat exchange apparatus according to claim 1, wherein the working fluid is water.
 17. The heat exchange apparatus according to claim 1, wherein the high-temperature fluid is the exhaust gas discharged from the water-cooled internal combustion engine, and the low-temperature fluid is the cooling water for the water-cooled internal combustion engine.
 18. A heat exchange apparatus comprising: an evaporation unit arranged in a high-temperature fluid path with a high-temperature fluid flowing therein for exchanging heat between an evaporable and condensable working fluid sealed in the evaporation unit and the high-temperature fluid thereby to evaporate the working fluid; a condenser unit arranged in a low-temperature fluid path with a low-temperature fluid flowing therein for exchanging heat between the working fluid evaporated in the evaporation unit and the low-temperature fluid thereby to condense the working fluid; an evaporation-side communication unit for leading the working fluid evaporated in the evaporation unit to the condenser unit; and a condenser-side communication unit for leading the working fluid condensed in the condenser unit to the evaporation unit; wherein the evaporation unit includes a plurality of heat pipes arranged in such a manner that the working fluid flows in a non-horizontal direction and outer fins for increasing the area of heat transmission between the heat pipes and the high-temperature fluid; and wherein the working fluid is circulated through the evaporation unit and the condenser unit; the apparatus further comprising condenser-side shield plates for preventing the high-temperature fluid from flowing to the condenser-side communication unit. 